Multioffice automatic telephone system



Oct 17, 1933 A. KEYSER Er AL l,930,522

MULTIOFFICE AUTOMATIC TELEPHONE SYSTEM `Filed March 19, 1932 3 Sheets-Sheet 1 UCL 17, 1933- A. KEYSER ET Al.

.MULTIOFFICE AUTOMATIC TELEPHONE SYSTEM 3 Sheets-Sheet 2 Filed March 19, 1932 Oct. 17, 1933. A. KEYSER Er AL MULTIOFFICE AUTOMATIC TELEPHONE SYSTEM Filed March 19. 1932 3 Sheets-Sheet 3 Patented Oct. I7, 1933 MULTIOFFICE AUTOMATIC TELEPHONE SYSTEM Alfred Keyser and Franz Simon, Berlin, Germany, assignors to Siemens & Halske Aktiengesellschaft, Wernerwerk Siemensstadt, near Berlin, Germany Application March 19,

1932, serial No. 599,918,

and in Germany April 23, 1931 9 Claims.

This invention relates to automatic telephone systems provided with exchanges connectedin series by junction lines accessible over free hunting switches.

One feature of the invention has for its object to facilitate the setting up of a connecting route in the required traine 'direction in a simple and reliable manner. This is achieved by switching means which are caused to operate dependent on a switching operation carried out for determining the particular use to be made of common junciion lines and which automatically applies alternating currents of denite frequencies successively to junction lines leading to exchanges and control switching devices arranged in the exchanges for the purpose of forming a connecting route to the required exchange.

This arrangement Oilers specialadvantages in systems provided with a plurality of exchanges in series due to the fact that a connecting route, extending over a plurality of exchanges may be set up with reliablity.

Another' feature has for its object to set up with great rapidity a connecting route from the calling to the required exchange in such a system independently of the location of the required exchange, this being achieved due to the exchanges being provided with switching devices which preparatorily ccnnect together idle junction lines between the exchanges thus forming a connecting route extending over the series connected exchanges.

By this arrangement a connecting route extending over all the series connected exchanges is, therefore. set up already prior to the transm'ssion of impulses characterizing the traic direction with the result that the required exchange may be immediately reached even if a large number of exchanges are concerned.

An embodiment of the invention is shown in Figs, 1-4, Fig. 1 showing diagrammatically the system of :interest in this case Whereas Figs. 2-4 show the individual circuits of the switch train of this system.

As will be seen in Fig. l, the subscriber T1, associated with a main exchange and shown in this figure, is able to reach subscriberscf various satellite exchanges, for example, the subscriber T4 associated with the satellite exchange 1, the subscriber T5 of the. satellite exchange 2 and the subscriber T6 associated with the satellite exchange 3. ,Y

When the subscriber Tl lifts his receiver the call finder AS1 starts hunting for the calling subscribers line and the preselector VWl for an idle lirst group selector, the subscriber T1 being switched through to an idle group selector for example, GWl when the above two switches are brought to rest. Said group selector GWl now being set to a denite level, in any known manner, by the transmission of number impulses hunts in this level for an idle succeeding second group s-elector, for example, GWZ. The group selector GWZ may also be iniluenced by impulses sent out by the calling subscriber Tl.

If the subscriber Tl wfshes to set up a connection with the subscriber T4 associated with the satellite exchange l, an impulse series comprising one impulse only is transmitted which sets the second group selector GWZ to the rst level in which it hunts for a free repeater, for example, y

Uel,

Said repeater Uel is connected over a preselecting secondary line switch MWl to the repeater U23, without, however, said repeater U83 being guarded by the secondary line switch against seizure by other secondary line switches which, likewise, are lcapable of seizingA this repeater. The repeater U63 is also connected over the secondary line switchfMW in the satellite exchange 2 which, likewise, is preselectively set without furnishing a guard to the repeater Ue6 in the satellite exchange 3 over the repeater Ue5. It will` thus be seenithat a direct connection exists between the group selector GW2 and the repeater U66 in the satellite exchange 3.

When the group selector GW2 has reached the repeater Uel over its'nrst level in the manner suggested above,a definite signal according to the setting of said group selector is sent out from the repeater Uel lin the form of ak denite frequency. How this signalis produced will be fully explained in a later paragraph. Said signal which denotes the required satellite exchange iniluences the identifying devices arranged in the Various satellite exchanges, thus, in the satellite exchange 1 the identifying device KEl, the identifying 'device KEZ in the satellitexexchange 2 and the identifying device KE3 inthe satellite exchange 3. A connection being denoted to the satellite exchange l over the nrst level ,of the group selector GW2 due to the seizure of the repeater Uel. The identifying devices KEl in the repeater U62 causes a change`r over in such a manner that the secondary line switch MWl associated with the change-over position rU1 is disconnected and consequently they secondary line switch MWZ'is connected up. preselected an idle nal selector, for example, L WZ'without, however, having guarded said final It, likewise, has

selector from being seized by other secondary line switches. The guarding of the nal selector LW2 is effected as soon askthe connection is switched over to it in a manner to be described later. The repeaters U63-U66 may now be used for the setting up of additional connections.

When the subscriber T1 transmits two addi.- tional impulse series, the first one will cause a final selector Lw2 to be raised accordingly, the second one causing it to rotate until the required subscriber T4 is reached. The speaking connection between the subscriber T4 of the satellite exchange 1 then extends from the group selector GW2, over the repeaters U61 and U62, the secondary line switch MW2 and. the final selector Should the subscriber T1 wish to set up a connection with the subscriber T5 associated with the satellite exchange 2, instead of sending out one single impulseY with the object of setting the group selector GW2 he transmits an impulse series comprising two impulses which cause the group selector GW2 to be raised to the second level. The group selector GW2 in this level hunts for an idle repeater which might be the repeater U61 shown in Fig. 1. Since this repeater, however, was seized over the second level of the group selector GW2, an identification signal L different from that transmitted in the case of -of theY succeeding impulses.

the previous connection will be sent out to said repeater. The identifying devices KEl, XE2 and KES are inuenced by said signal, but the effect in this case is that a change over will be carried out in the repeater U64 of the satellite exchange 2, causing the secondary line switch MW3 to be disconnected and the secondary line switch MW4 to be connected up. This secondary line switch MW4 also has preselected a final selector for example LW4 without, however, guarding this final selector. Only in this moment is the guarding set up at the secondary line switches MWl and MW4. The final selector LW4 is then set to the required subscriber T5 by the succeeding two impulse series to be sent out by the subscriber T1. The speaking connection between the subscriber T1 and T5 thus extends from the group selector GW2 over the repeater U61, the secondary line switch MWl in repeater U62, the repeaters U63 and U64 aswell as over the secondary line switch MW4 and the final selector For the purpose of setting up a speaking connection between the subscribers Tl and T6 associated with the satellite exchange 3 the group selector GW2 is raised to the `third level in consequence or" an impulse series comprising three impulses. The groupV selector may in this levelY again reach the repeater U61 shown in Fig. 1, if it is idle. Due to it being seized over the third level, however, still another identification signal different from those already used has to be sent out. This signal influences the identifying devices KEl, XE2 and KE3 in such a manner that the change-over stations U1 and U2 remain in the position shown, but a final selector LW5 in the satellite exchange will be placed at the disposal It should -be mentioned that only the repeater seized rby the secondary line switches MW1 and MW 3 is now guarded. When the subscriber now transmits the two last impulse series the final selector LW5 is accordingly set tc the required subscriber T6.

VThe speaking connection then extends from the group selector GW2 over the repeater U61, the econdary line switch MW l in the repeater U62,

repeater U63, secondary line switch MW 3 in the repeater U64,` repeaters U65, U66 and final selector LW5. Y

In addition to the connecting facilities described above, the subscribers associated with the individual satellite exchanges may also be interconnected as well as connected to subscribers associated with other satellite exchanges. Thus, for example, the subscriber T2 is able to reach a final selector LW 1 over the call finder A532 and preselector VW2, in which case said final selector LWl may be set either to a subscriber of the same satellite exchange T4 or, alternatively, to the repeater U63. The repeater UeS in the same manner as repeater U61 is capable of influencing the identifying devices in the various satellite exchanges by sending out different identification signals in accordance with the access over which it was seized by the iinal selector LWl. Thus, for example, the change over device U2 in the satellite exchange 2 is actuated in the case of seizure from a particular means of access with the result that the secondary line switch MWS is disconnected and MW4 connected thus causing, for example, the final selector LW4 in the satellite exchange 2 to be guarded. The subscriber T5 associated with the satellite exchange 2 may then be reached by the appropriate setting of the nal Vselector LW4. l

If the inalselector LWl, however, is set by another impulse series, sent out by the calling subscriber T2, and consequently reaches the repeater U63 over another access, said repeater transmits a diierent signal which causes no change over in the repeater U64, but instead places the final selector LW at the disposal of the calling subscriber T2 over the repeaters U65 and U66, with the result that said final selector w13.775 rmay be set to the subscriber T6 associated with the satellite exchange 3.

In the saine manner a subscriber T3 may eithe reach a subscriber of the saine satellite exchange or asubscriber associated with the satellite ex change 3.

In addition, it should be ncted that the method of setting the impulse receivers is quite inimaterial as regards the feature of this invention. This setting may, for example, be effected by direct current impulses or alternating current selection as assumed for the individual circuits shown. The circuits required for the selection have not been shown and they may take ,any shape or form of no interest in the present case. The release of the repeaters and switches concernedk is also of no interest and consequently will not be described.

Figs. 2-4 are to be joined together for the succeeding specification and in such a` manner that the secondary line switch MWl (Fig. 2) is connected to the repeater U63 in Fig. 3 secondary line switch MWB of this figure is connected to the repeater Ue'in Fig. 4. Accordingly relay P1 associated with the secondary line switch MWI in Fig. 2, is energized over: earth, .l windings 1 and II of relayAPi, wiper of the secondary line switch IvIWl, contact 1067131 (Fig. 3) resistance Wi12, battery, earth. Relay P2 assoc iated with the secondary line, switch MWS in 1Eig. 3, is likewise energized over: I and Il or relay P2, wi er of the secondary line switch MWB, contact 1707132 4), resistance Wi23, battery, earth. l

The energizing circuits for the rotary magnets D1 or D3 of the above mentioned secondary 1 and the earth, windings 1 line switches are therefore cut orf at contacts 51111 (Fig. 2) or 149112 (Fig. 3).

Y Assuming, in lrelation to the description of the individual circuits shown in Figs. 2-4, that a subscriber T1, as indicated in Fig. 1, has reached the group selector GWl over the call finder AS1 and' preselector VWl and subsequently the group selector GW2 after completed setting on the part of said group selector GWl. If the group selector GW2 is now iniluenced by alternating current impulses, the various connections, broadly explained above, are set up in the following manner:

(1) Setting up a. connection between the subscriber T1 associated with, the main exchange and the subscriber T4 associated with the satellite exchange 1 The subscriber T1, for the purpose of setting the group selector GW2, sends out an impulse by means of which, in a manner of no interest in this case, said group selector is set to the first level in which it may reach the repeater Uel as indicated in Fig. 2. This repeater is seized due to relay C1 being energized over the c-wiper and the contact bank of the rst'level by a not shown earth potential in the preceding selecting stage (GWl) in the following circuit: earth, battery, contact 1771.3, relay C1, c-wiper of the group selector GW2, to earth potential applied to preceding switch. The closing of contact 901 energizes relay A over the following circuit: earth, battery, relay A, contacts 271.1, 901, earth. An alternating current impulse of a frequency of 50 cycles derived, from an alternating current source of supply W1 is transmitted by the closing of contacts 78a and 80a over the leads shown in Fig. 2 with the object of influencing the identi- 'tying devices in the various satellite exchanges. The effect of this alternating current impulse will be described in a later paragraph.

Due to the energization of relay A the relay H1 will be energized, in addition to the transmission of the alternating current impulse, over contact a in the following circuit: earth, contact 30a, relay H1, resistance Wz2, battery, earth, This relay is placed in a locking circuit over its contact 29H1. Relay A is disconnected from battery by the opening cf contact 2h1 and the alternating current source of supply W1 is consequently disconnected at contacts 78a and 80a. By the closing of contact 12h1 relay A1 will now be energized over: earth, battery, relay A1, contacts 12H1, 13h2, 1403, 15c2, and earth, with the result that by the closing of contacts 82111 and 84a1 an alternating current source of supply W2 which sends out an alternating current impulse of a frequency of 10i) cycles over the shown junction line will be connected up. The eiect which this alternating current impulse has upon the identifying device will also be described later. The energization of relay A1 causes, further, an energization of relay H2 over: earth, contacts 19ml, 20c1, relay H2, resistance Wi4, battery, earth. The closing of contact 2811.2 energizes relay H3 over: earth, contact 28h2, relay H3, resistance Wi6, battery, earth. Relay A1 is disconnected from battery by the opening of contact 13h2 and the alternating current source of supply W2 is consequently disconnected by the opening of contacts 82a1 and 84a1. The resistance Wil is connected up over contact 18h2 with the result that since, upon the energization of relay H3, the contact 17713 is opened, the repeater Uel, reached bythe group selector GWZ, cannot be seized by any other group selector. Relays H2 and H3 are maintained energized over contact 26h3. i

The alternatng'current impulses of diierent` frequencies sent out successively from the alternating current sources of supply W1 and W2 inuence relays X1, Y1 intherepeater Ue2: X2, Y2 in the repeater Uc4 and X3, YS in the repeater Ue6, which are tuned to the corresponding frequencies. Relay X1 is tuned to the frequency of cycles and is associated with the repeater Ue2 and is influenced by the alternating current source of supply W1. i

Relay Col is energized by the closing of contact 40x1 in the following 'circuiti earth, contacts 4001, 43e1, winding I of relay Col, resistance Wz'7, battery, earth. Relay Hol is energized over ccntact 460:1. By the closing of contact co1, the guarding of the line reached by the secondary line switch is maintained by the closing of contact 53ml. The secondary line switch MWl seized the repeater Ue3 in its normal position. It thus caused relay P1 to be energized over: earth, windings I and II of relay P1, secondary line switch MWl, repeater Ue3, contact 106h31, resistance Wi12, battery, earth. The repeater Ue3 is guarded by the short circuit of winding I of relay P1 as indicated above. Relay X1 releases when the alternating current source of supply W1 is disconnected, whereupon an alternating current impulse of a frequency of 100 cycles influences relay Y1, tuned to this frequency, by the connecting up of the alternating current source of supply W2. Relay Col is now reenergized over contact 391/1. The closing of contact 471/1 causes relays U1 and S1 to be energized (relay Hol is still maintained energized after the de-energization of relay X1 due to the fact that it is constructed as a slow acting relay) over: earth, contacts 47y1, 48h01, windings I of relays U1 and S1, battery, earth. The opening of contact 6731 removes the guarding of the repeater Ue3 seized by the secondary line switch MWI. A change over in the repeater Ue2 to the secondary line switch MW2 is effected by the closing Vof contacts 7711.1, 74151 and 204u1 associated with relay U1. Relay U1 is maintained energized with its winding II over: earth, contacts 55co1, 204u1, winding II of relay U1 and battery in the not shown secondary line switch MW2.

As will be seen from Fig. 1, the subscriber T1 thus, in a manner ofno interest in the present case, may reach, for example, the final selector LW2 in the satellite exchange l1 over the sec- `ondary line switch MW2. He can now cause this nal selector LW2 to hunt for the required subscriber T4` by issuing an additional series of impulses.

Upon the de-energization of relay Y1 when the alternating current source of supply W2 is disconnected, relay Col remains energized over 'its winding II simultaneously energizing relay El over: earth, contacts 361/1, 35001, winding II of relay Col, contact 42ml, relay El, battery, earth. Relay C11 which is maintained energizedover contact 58c11 is energized over contact 56001. Relay C21 is energized bythe closing of contact c11 in the following circuit: earth, Vcontact 65011, relay C21, resistance Will, battery, earth. Relay C21 remains. lenergized over contact 63021.

The action the alternating current impulses has on relays X2 and Y2 in the repeater Ue4 (Fig. 3), said impulses being sent out by the repeater Uel as described above, is as follows: Relay X2 in the repeater U64 id energized by the alternating current impulse of a frequencyof 5 0 cycles transmitted over the leads of the junction line. Consequently, relay C03 will be energized over contact 1262. This circuit extends as follows:V earth, contacts 126112, 12962, winding I` of relay C03, resistance Wil8, battery, earth.V Relay C03 is energized in this circuit. An earth potential is applied at contact 147032 so as to guard the repeater Ue5 reached over the second-- ary line switch MW3, said repeater U65 being seized by the secondary line switch only.

When relay X2 is disconnected from Abattery at the end Yof the alternating current impulse cfa frequency of 50 cycles, relay C03 is deenergized bythe opening of contact 126322. If additional alternating current impulses of 100 cycles are transmitted from the repeater Uel, relay Y2 which is tuned to a frequency of 100 cycles is energized and causes an energization of relay H02 over contact l27y2. Since a change over in the repeater U82 (Fig. 2). to the secondary line switch MW2 is effected at the contacts of relay Ul in the manner described above no further switching operations occur in the repeater Ue4. Relay H02 is, therefore, disconnected from battery and the guarding of the repeater` Ue5 is removed- The alternating current impulses have the following iniiuence on the relaysassociated with the repeater Ue6 (Fig. 4)

Relay X3 is energized by the alternating current impulse of a frequency of 50 cycles and causes an energization of relay C04 by the closing of contact 285933 in the following circuit: earth, contacts 185:1?3, 191e3, winding I of relay Coe, resistance Wi28, battery, earth.

Relay X3 releases at the end of said alternating current impulse and consequently causes the re lease of relay C04.

The alternating current impulse of a frequency of 100 cycles then causes relay Y3 to be energized. Since the change over in the repeater takes place now, no further switching operations can occur in the repeater U66.

2. Setting up a connection between the subscriber T1 associated with the main exchange and the subscriber T5 Vassociated with the satellite'echange 2 In order to set up the connection the subscriber Tl sends out an impulse series comprising two impulses with the object of setting the group selector GW2. These impulses cause the group selector GWZto be raised to the second level. In this level the group selector GW2 may find the repeater Uel to be idle with the result "hat relay C2 in the repeater Uel is energized over the c-wiper of the group selector GW2. This circuit extends as follows: earth, battery, contact l'lhB, relay C2, c-wiper ofthe. group selector GWZZ, and earthpotential Ain the not'shownjpreceding group selector. Relay-A1 will now be energized-by the closing of contact 16c2 in the following circuit: earth, battery, relay Al,`c0n tacts llhl,` 15c2, earth. .The closing of contacts 82a1 and 84cl connects up the alternating current source of supply W2, Vthus sending out an alternating 'current impulse of a frequency of liti) cycles to influence the identifying devices in the various satellite exchanges; Relay H1 is energized by Contact Blal over: earth, contact Slal,

relay Hl, ,resistance Wi2, battery, earth, and is maintained energized over its contact 29h1. The opening of contact llhl disconnects relay A1 from cattery and consequently also disconnects the al- Vtending over contact 63021). No further switch- The guarding of the repeater Ue5, already caused ternating current source of supply W2. This re-r sults in an energization of relay A as follows: earth, battery, relay A, contacts Shl, 171.2, v16c2, earth.- The closing of contacts 78a and 80a connects up the alternating current source of supply W1 to the leads of the junction line, whereupon an alternating current Aimpulse of a frequency` of 50 cycles will be sent out.A When relay A is energized, relay H2 also=is caused to be energized over: earth, contacts 21a, 2202, relay H2, resistance Wi4, battery, earth. The opening of Contact 1&2 disconnects relay A from battery and consequently also disconnects the alternating current source of supply W1. Relay H3 is energized by the closing of contact 28H2 over: earth, contact 28h2, relay H3', resistance WiG, battery, earth. Relays H2 and H3 are maintained energized over contact 26h3. The resistance Wil is connected up by the contact 18h2 lwith the result that, since the contact 17h23 is opened due to the energization of relay H3, the repeater U61 cannot be seized by any other group selectors.

The alternating current impulses transmitted from the repeater in the order 100 cycles- 50 cycles cause the following switching operations to be performed in the satellite exchanges: relay Y1 tuned to a frequency of 100 cycles is nrstinnuenced in the repeater Ue2 with-v the result that relay Col is energized over contact 393/1 in the followingy circuit: earth, contacts 391/1, 43e1,'winding l of relay C01, resistance Wi?, battery, earth. `When relay Y1 releases at the end of the alternating current impulse, relay Col will be de-energized but is reenergized upon the energization of relay X1 over Contact 491:1 due to the alternating current impulse of a frequency of 5i) cycles. Relay X1 releases at the end of this alternating current impulse whereupon relay C01 is maintained energized over its winding H and at the same time causes relay El to be energized over: earth, contacts 36311, 3501, winding H-of relay Col, contact 42ml, relay El, battery, earth. After the repeater Ue3, reached by the secondary line switch MWI due to an earth potential being applied at con tact 531/1, has been guarded in the manner described above, said guarding will be maintained at contact 55001. Y,

The connection now remains switched through over the secondary line switch MWl to the repeater Ue3 (Fig. 3). Relay C11 is energized by the closing of contact 56001 and is maintained energized over contact. 58011. Relay C21 is energized over contact 65c1l (locking circuit exing operations will take place in the repeater Ue2. i YThe following switching operations will be initiated in the repeater Uc-i, however, bythe transmission of the alternating current impulse: The relay Y2 which is tuned to a frequency of 100 cycles is rst energized. Thereupon the relay Ho2 is energized over contact 127y2. Relay Y2 releases at the end of the alternating current impulse. Relay X2 is now energized by the alternating current impulse of a frequency of 50 cycles and in turn causes energization of relay VC03 over: earth, contacts 126532, 129e2, winding I or relay C03, resistance Wil, battery, earth.

by contacts 147:62 and le5y2 is maintained over the secondary line switch MWE by the closing of contact 146003. Further, the relays U2 and S2 are energized over: earth, contacts l26r2 129e2, 138ho2, windings I of relays U2 and S2, battery, 15() current source of supply Wl.

earth. When relay X2 releases at the end of the alternating current impulse of a frequency of cycles, relay C03 is maintained energized over its Winding II and at the same time causes the energization of relay E2 over: earth, contacts 125322, 122003, winding II of relay C03, contact 128y2, relay E2, battery, earth. The guarding of the repeater Ue5 (Fig. 4) is again removed at contact 15032 by the above mentioned energization of relay S2, Whereas the secondary line switch MW4 will be connected up at contacts 1551,52, 153a2, and 151u2 of relay U2 in place or" the secondary line switch MW3. Relay U2 then remains energized with its Winding II over: earth, contacts 146003, 1511.42, winding II of relay U2, to battery in the not shown secondary line switch MW4. The closing of contact 141003 energizes relay C13 and causes it to be maintained energized over contact 143013. By closing contact 13lc13 it causes relay C23 to be energized which in turn is maintained energized over contact 135023.

The secondary line switch MW4 is preparatorly set to a nal selector LW4 in the manner indicated in Fig. 1. When the calling subscriber T1 sets this nal selector to the required subscriber T5, the speaking connection is completed.

' The transmission of alternating current impulses produces the following switching operations in the repeater UeG:

The energization of relay YS causes an energization on the part of relay E3 (alternating current impulses of a frequency of cycles) over: earth, contacts 211025, 210015, 212:1;3, relay E3, battery, earth.

When, at the end of this impulse series, relay YS releases, the relay E3, being constructed as a slow acting relay, is still operated, and is maintained energized over Contact 185:03 of relay X3 which is energized on receipt of the succeeding alternating current impulse of a frequency of 50 cycles.

When relay X3 releases at the end of this impulse, relay E3 also is ole-energized after a short period with the consequence that the repeater j Ue will be restored to normal.

3. Setting up a connection between the subscriber T1 associated with the main echange and the subscriber T6 associated with the satellite ea:- change 3 The group selector GW2 with the object of setting up this connection is set to the third level by the calling subscriber .T1 so that, on the assumption that the iirst idle repeater encountered j is the repeater Uel, shown in Fig. 2, relay C3 will be energized over the c-wiper over: earth, battery, contact 17h3, relay C3, c-Wiper of the group selector Gw2, earth applied to the preceding group selector. The closing of contact '7c3 energizes relay A over: earth, battery, relay A, contacts 2h1, '703, 1001, earth. An alternating current impulse of a frequency of 50 cycles from the alternating current Source of supply W1 is transmitted upon the closing of contacts "18a and 80a to the identifying devices of the various satellite exchanges. Relay Hl is energized over contact 30a `causing relay A to be ole-energized on the opening of contact 2h1, thus, at the same time disconnecting the alternating The opening of contact 25h1 removestheshort circuit for relay H2 with the result that this relay is energized. 1n-energization of relay H3 is then -caused over contact 28h2. Relays H2 and H3 are placed in a locking circuit over contact 26h3. An alternating current impulse of a frequency of 50 cycles is consequently sent out from the repeater Uel. This impulse influences only relay X1 in the repeater Ue2 with the result that relay C01 is energized in the following circuit due to the de-energization of relay X1 and at the same time causes relay E1 to be energized over: earth, contacts 36y1, 35001, winding II of relay Col, contact 42.701, relay E1, battery, earth. The repeater Ue3, reached by the secondary line switch MWL is guarded in the manner already described in several instances. After relay Col has been energized, relay C11 is also caused to be energized over contact 50001. Relay C11 causes an energization of relay C21 by closing contact 65611.

Relay X2 in the repeater Uel (Fig. 3) is influenced by the alternating current impulse of a frequency of 50 cycles and causes relay C03 to be energized over its contact 126r2 in the following circuit: earth, contacts 126322, winding of relay C03, resistance VM18, battery earth. Relay C03, upon de-energization of relay X2, is maintained energized with its winding II, at the same time causing an energization of relay E2 over: earth, contacts 125x2, 122003, winding II of relay C03, contact 128y2, relay E2, battery, earth. No further switching operations occur in the repeater Ue4 in addition to the guarding of the repeater Ue5 described in several instances after energization of relay C13 over contact 141003 and the subsequent energization of relay C23 over contact 131013.

The alternating current impulse causes the following operations in the repeater Ue6 (Fig. 4). Relay X3 is actuated and closes its contact 185203 which in turn causes an energization or" relay C04 over: earth, contacts 185r3, l91e3, winding I of relay C04, resistance Wi28, battery, earth. Relay C04 is maintained energized over its WindingII after relay X3 has released but at, the same time causes relay E3 to be energized over: earth, contacts 131.733, 183004, WindingII of relay Col, contact 189y3, relay E3, battery, earth. Relay C15 is energized over contact 193004, causing relay C25 to be energized over contact 197015 and subsequently relay C05 to be inuenced over contacts 203025 and 20203. The final Yselector LW5 in the satellite exchange 3 is seized and guarded by relay C05 in a manner of no interest in the present case. The calling subscriber T1 may now set the final selector to the required subscriber by transmitting additional impulses.

In the manner shown in Fig. l, the Vvarious subscribers associated with the satellite eX- changes are in a position to lset up connections either to subscribers associated with the same satellite exchange or to subscribers associated with other satellite exchanges.

4. Setting 'ap a connection between the subscriber T2 associatedwith the satellite exchange 1 and the subscriber T5 associated with the sat-V eZZite exchange 2 Y As will be seen from Fig. 1, the subscriber T2 is able to reach ay final selector LWl over the call nder AS2 and preselector VW2. By sending out two impulse series the subscriber T2 may set the nal selector LW 1 to a deiinte Contact of a level in a manner of no interest in this case and thus ico seize, for` example, the repeater Ue3, shown in Fig. 3, over the test lead C12. Relay C12 is energized over this lead by an earth potential applied in any suitable manner to the final selector LW1 (earth applied to the final selector LW1, lead cl2, relay C12, contact 106h31,'resistance Wi12, battery, earth). The closing'of Contact 104012 energizes relay A22 over: earth, battery, relay A22, contacts 1057111, 101c12, earth. The alternating current source of supply W21 is connected to the leads of the shown junction line over the contacts 93a22 and 95a22and transmits an alternating currentimpulse of a frequency of cycles. Relay H11 is energized by the closing of contact 109a22 in the following circuit: earth, contact 109a22, relay H11, resistance Wi14, battery, earth. Relay H11 is thus energized in ythis circuit'and by the opening of contact 105h11 causes relay A22 to be de-energized. By the closing of contact 98h11, relay A12`will be energized over: earth, battery, relay A12, contacts 98h11, 97h21, 104c12, earth. The alternating current source of supply W11 is connected to the leads of the junction line over contacts 90a12 and 92a12 with the object of transmitting cycles. The removal of the short-circuit at contact 117h11 causes relay 1-121 to be energized over: earth, contacts 115a12, 116012, relay H21, resistance Wild, battery, earth. The closing of contact 121h21 energizes relay H31 over: earth, Contact 121h21, relay H31, resistance Wi1'7, battery, earth. The opening of contact 97h21 de-energizes relay A12 and consequently disconnects the alternating current source of supply W11. A resistance Wi32 is connected up in the circuit by the opening of con tact 106h31 and the closing of contact 107h21 and this prevents the repeater Ue3 from being seized by another side. Relays H21 and H31 are maintained energized over contact 119h31.

The alternating current impulses transmitted from the alternating current sources of supply W21 and W11 influence the individual repeaters in the manner described under heading 2. The only difference in operation is that the reached final selector may be set by the subscriber T2.

5. Setting ap a connectionbetween a subscriber T2 associated with the satellite exchange 1 andthe subscriber T6 associated with the satellite exchange Y3 A52 and preselector .VW2 (Fig. 1), is set in such a manner that it reaches the repeater Ue3,

shown in Fig. 3, over the test lead C22. The following circuit is then completed: earth applied to the nal selector LW1, lead C22, relay C22,.con tact 106h3l, resistance Wi12, battery, earth. Relay C22 is energized in this circuit and by the closing of its contact 101c22 causes relay A12 to be energized over: earth, battery, relay A12, contacts 99h11, 101c22, earth. The alternating current source of supply W11 is connected to the lead of the junction line over contacts 90a12 for the purpose of sending out an alternating current impulse of a frequency of 50 cycles. Due tothe closn ing of contact 108a12, relay H11 will be energized over: earth, contact 10Sa12, relay H11, resistance Willi, battery, earth; The energizing circuit for relay A12 is cut olf at contact 99h11 thus causing the alternating current source of supply W11 to be disconnected. After removing the short circuit at contact 1177111, relay H21 is energized over contact 118c22 in the following circuit: earth,

Contact 118c22, relay H21, resistance Wi16, battery,earth. The closing of contact 1217121 energizes relay H31 over: earth, contact 121h21, relay H31, resistance Wil'l, battery. earth. Relays H21 and H31 are maintained energized over contact 119h31. No further alternating current impulses are nowV transmitted from'the repeater Ue3. The switching operations already described under heading 3 are initiated in the other repeaters due to this individual alternating current and upon the completion of said switching operations the final selector LW5 may be set by the calling subscriber T2 to the required subscriber 6. Setting up a connection between the subscriber T3 associated with the satellite exchange 2 and the subscriber T6 associated with the satellite exchange 3 As will be seen from Fig. 1 the subscriber T3, after setting the call finder ASB and the preselector VWS reaches a final selector LW3 which said subscriber may set by transmission of Vnumber impulses to a contact over which the repeater Ue5 is reachable. This repeater Ue5 is therefore seized over the test lead C14 in the manner shown in Fig. 4, and thus influences relay 14 in a manner of no interest in the present case. The closing of contact 174c14 energizes relay A13 over: earth, contacts 174c14, 1'73h12, relay H13, battery, earth. An alternating current source of' supply W12 is connected up to the leads ofthe junction line over contacts 165a13 and l67a13 for the purpose of transmitting an impulse of a frequency of 50 cycles. Upon the energization of relay A13, relay H12 Will also be energized over: earth, contact 175a13, relay H12, resistance Wi24, battery, earth. The opening of Contact 173h12 disconnects relay A13 and, at the same time, the alternating current source of supply'W12 from battery, at contacts 165a13 and 16'7a13. Relay H22 is energized over contact 176h12 upon 1 the opening of contact 179h12 (earth, contact 1'76h12, relay H22, resistance W1226, battery, earth), and, by the closing of contact 182h22, energizes relay H32. Relays H22 and H32 are maintained energized over contact Relay X3 in the repeater Ue6 is influenced by the alternating current impulse of a frequency of 50 cycles and, in the manner described under heading 3, seizes the final selector LW5 whereupon this can be set to the required subscriber.

What is claimed is: 1. A telephone system comprising a main exchange and a plurality of sub-exchanges, a trunk line connecting said main exchange and said subexchanges in series, a repeater in said main exchange arranged to send out coded alternating current impulses over said trunk line, identifying devices in said sub-exchanges for receiving said alternating current impulses, said identifying devices comprising means for selectively connecting the sub-exchanges to said trunk line, and means in each of said sub-exchanges for extending said trunk line to a called party.

2. In a telephone system a main exchange and a sub-exchange, a trunk line connecting said main exchange and said sub-exchange, a repeater in Ysaid main exchange arranged to send out coded alternating current impulses over said trunk line, an identifying device in said subexchange for receiving said alternating current impulses, said identifying device comprising means for connecting said sub-exchange toV said trunk line, and means in said sub-exchange for extending said trunk line to a called party.

3. In a telephone system a main exchange and a sub-exchange, a trunk line connecting main exchange said sub-exchange, automatic switching means in said main exchange, a repeater in said main exchange, means for selecting said repeater, said repeater comprising means for sending out coded alternating current iinpulses, a second repeater said sub-exchange comprising means for receiving said alternating current impulses, a switching device in said second repeater comprising means for connecting said sub-exchange to said trunlr line, automatic switches in said sub-exchange, and means for controlling said automatic switches to extend said trunk line to a called party.

4. In a telephone system, a main exchange and a sub-exchange, a trunk line connecting said main exchange and said sub-exchange, automatic switching means in said main exchange, a repeater in said main exchange, means for selecting said repeater by said automatic switches, said repeater comprising means for sending coded alternating impulses over said trunk line, a second repeater in said sun-exchange, an identifying device and a switching device included in said second repeater, said identifying device including means for receiving said impulses, said switching device comprising means for connecting said sub-exchange to said trunk line, automatic switches in said sub-exchange, and means for controlling said automatic switches to extend said trunk line to a called party.

5. In a telephone system a main exchange, a first sub-exchange and a second sub-exchange, a trunk line connecting said main exchange and said sub-exchanges in series, a repeater in said main exchange, a second repeater in said rst sub-exchange, a third repeater in saidv second sub-exchange, said rst repeater comprising means for sending coded alternating current impulses corresponding to the code for said second sub-exchange over said trunk line, means controlled by said third repeater for connecting said second sub-exchange to said trunk line, and means in said sub-exchange for extending said trunk line to a called party.

6. In a telephone system, a main exchange, a rst sub-exchange and a second sub-exchange, a trunk line connecting said main exchange and said sub-exchanges in series, said trunk line comprising a section extending `from said main exchange to said rst sub-exchange and a second section extending said first sub-exchange to said second sub-exchange, automatic switching means in said main exchange, a repeater in said main exchange, means for operating said automatic switches to select said repeater, a second repeater in said rst subexchange, an identifying device and a switching device in said second repeater, av rotary line switch in said second repeater comprising means for preparatorily connecting said sections, a third repeater in said second sub-exchange, a second identifying device and a second switching device in said third repeater, said first repeater comprising means for sending coded alternating current impulses corresponding to the code for said second sub-exchange over said trunk line, said second identifying device comprising means for receiving said impulses, said second switching device containing means for connecting said second sub-exchange to said trunk line, automatic switches in said second sub-exchange, and means for controlling said automatic switches to extend said trunk line to a called party.

'7. In a telephone system, a rst sub-exchange and a second sub-exchange, a trunk` line connecting said sub-exchanges, a repeater in said first sub-exchange, automatic switching means in said rst sub-exchange, means for operating said automatic switches to select said repeater, a second repeater in said second sub-exchange, an identifying device and a switching device in said second repeater, said first repeater comprising means for sending coded alternating current impulses corresponding to the code for said second sub-exchange, said identifying device containing means for responding to said impulses, said switching device comprising means for connecting said second suie-exchange to said trunk line, automatic switches in said second subexchange, and means for controlling said automatic switches to extend said trunk line to a called party.

8. In a telephone system, a main exchange and a sub-exchange, a trunk line connecting said main exchange and said sub-exchange, a repeater in said main exchange arranged to send out coded alternating current impulses over said trunk line, an identifying device in said subexchange fo,` receivingl said alternating current impulses and connecting said sub-exchange to said trunk line, means in said identifying device for guarding said trunk line, and means in said sub-exchange for extending said trunk line to a called party.

9. In a telephone system comprising a main exchange and ak pluralityv of sub-exchanges, a trunk line connecting said main exchange and said sub-exchanges in series, a repeater in said main exchange, a plurality of switching means in said repeater arranged to eifect the transmission of coded alternating current impulses of diiierent frequencies respectively, means for causing said switching means to function in a Vsequence dependent upon the route over which the repeater is taken into use, identifying devices in said suie-exchangesv for receiving said alternating current impulses, means in said identifying devices for selectively connecting the subexchanges to said trunk line, and means in each of said sub-exchanges for extending said trunk line to a called party.

ALFRED KEYSER.

FRANZ SIMON.

lGi) 

